Move binding functions into interop folder

Raylib-cs/interop/Raymath.cs

@@ -16,7 +16,7 @@ namespace Raylib_cs
     }
 
     [SuppressUnmanagedCodeSecurity]
-    public static unsafe class Raymath
+    public static unsafe partial class Raymath
     {
         /// <summary>
         /// Used by DllImport to load the native library

Raylib-cs/interop/Rlgl.cs

@@ -5,7 +5,7 @@ using System.Security;
 namespace Raylib_cs
 {
     [SuppressUnmanagedCodeSecurity]
-    public static unsafe class Rlgl
+    public static unsafe partial class Rlgl
     {
         /// <summary>
         /// Used by DllImport to load the native library